A purported inside look at General Motors Corp. by one of its former top executives portrays leaders of the nation's largest industrial firm as unconcerned about GM's substantial impact on American society.

More damaging, the assessment attributed to John Z De Lorean asserts that some GM executives knew well in advance of the fall 1959 introduction to the public of ill-fated Corvair cars that "serious questions" had been raised about their safety.

General Motors had no immediate comment.

"At the very most, there was a mountain of documented evidence that the car should not be built as it was then designed," De Lorean purportedly recalled.

"There wasn't a man in top GM management who had anything to do with the Corvair who would purposely build a car that he knew would hurt or kill people. But, as part of a management team pushing for increased sales and profits, each gave his individual approval in a group to decisions which produced the car in the face of the serious doubts that were raised about its safety," De Lorean is quoted as stating.

De Lorean's purported account of his career at GM was published yesterday under the title "On a Clear Day You Can See General Motors," by the former chief of Business Week's Detroit bureau, J. Patrick Wright.

Wright's byline appears on the book, but the former reporter said the highly critical assessment of GM is that of De Lorean. After a 17-year career at GM, one in which he appeared to outsiders to become heir-apparent as chief executive, De Lorean suddenly quit in early 1973. He now heads a firm that plans to introduce a new sports car.

Before departing GM, De Lorean had asked Wright to collaborate with him on a book offering an inside view of a large American Business. Playboy Press subsequently agreed to publish the book and made a $45,000 advance to the two men.

However, according to Wright, De Lorean later backed out of the project after providing the reporter with stacks of internal documents and hours of interview time. Wright said De Lorean "feared reprisals from GM would sink his attempts to launch a new car company." Thus, the book that appeared in stores around the nation yesterday was published without De Lorean's cooperation.

In a telephone interview yesterday, Wright said he quit work in 1978 to publish the book, that he had invested more than $100,000 of his own money to publish it privately, and that an initial order of 20,000 books was printed for sale at $12.95 apiece.

Wright said he wrote several times to De Lorean and Playboy Press, stating his plans to publish if they did not go ahead. Working under a clandestine publishing arrangement that appeared to rival some of the GM secrecy alleged in the book, Wright initially informed several reporters about the book late Tuesday.

"General Motors reaches a lot of businesses . . . I had to do it quietly," Wright said.

An aide said yesterday that De Lorean had not seen the book and would have no comment for now. Later, another aide called The Washington Post to obtain the name of the local bookstore where The Post bought copies early yesterday.

According to a General Motors spokesman, company executives also have copies. "No, we're not ready yet . . . but we may have some comments on the book later," he said. Playboy Press officials did not return a reporter's telephone calls, and Wright said he had not heard from any of the parties involved -- GM, De Lorean or Playboy.

De Lorean is a legend in Detroit. His father was a Ford factory worker and the young De Lorean worked on cars, attended engineering school and joined Chrysler before moving to the now-defunct Packard company. GM hired him in 1956 as head of advanced engineering at Pontiac and, at age 40, he became the Pontiac division's youngest head.

De Lorean took over the Chevrolet division in 1969, and in 1972 he became group vice president for North American operations. That put him in line to become GM president. In less than a year, however, he quit the $650,000-a-year post.

In the book published yesterday, De Lorean purportedly states that GM public relations people leaked a damaging draft of a speech in which he criticized the company's cars, thus diminishing his reputation in their heir-archy. "I was viewed as their token hippie," De Lorean is quoted as saying.

Currently, the 54-year-old De Lorean is getting ready to produce a two-seat sports car, called the DMC-12, with an engine in the rear. The cars will be built at a new factory in Northern Ireland for De Lorean Motor Co. and sold through a network of dealers in this country; of about 300 dealers currently signed up, 55 percent sell GM cars.

Wright says the former GM executive approved the book in 1975. Among its purported revelations:

In the wake of racial riots in Detroit in the 1960s, De Lorean proposed, and city officials eagerly paved the way for, construction there of a Pontiac assembly plant.The proposal was "rejected out of hand" by GM management, he purportedly said. "Memphis and Oklahoma City were chosen as the sites for new assembly plants in the face of compelling economic and social reasons for locating in Detroit."

"Never once while I was in General Motors Management did I hear substantial social concern raised about the impact of our business on America, its consumers or the economy."

Repeatedly, in the 1960s, proposals that GM start building smaller and more fuel-efficient cars were rejected. One reason GM management refused was that "we make more money on big cars."

GM pressed its executives to make substantial and possibly improper political campaign distributions, and it pressured dealers to buy GM parts that were more expensive than others.

"The best interests of the country were certainly not being considered when GM announced an average price hike of almost 10 percent per car in the summer of 1974, for inflation was already eating away at the average American family's income. It became a cold and calloused decision in my mind . . . the size of the increase was raised when (GM) learned that the pricing announcement would come at the time President Nixon resigned from office. The corporate bet was that all of the publicity given to the historic events taking place in Washington would overshadow and diminish the attention . . . And that is precisely what happened."

De Lorean himself does not escape criticism in his purported manuscript. "To me, the decisions that had to be made . . . like the switch to smaller cars, were so conspicuous and so obviously important to the future of General Motors that I should have found some way to communicate this to my superiors . . . I should have been able to sell my programs, which were so fundamental in nature and important to the corporation . . . I didn't do it. And I consider that to be the biggest failure in my business life at GM," he is said to have concluded.